[hopem,r=jamespage]

Ensure 'host' is set in cinder.conf if rbd storage backend is
related AND all backends are stateless e.g. rbd.

Closes-Bug: 1493931

hooks/cinder_contexts.py

@@ -3,12 +3,15 @@ from charmhelpers.core.hookenv import (
     relation_ids,
     service_name,
     related_units,
-    relation_get
+    relation_get,
+    log,
+    WARNING,
 )
 
 from charmhelpers.contrib.openstack.context import (
     OSContextGenerator,
     ApacheSSLContext as SSLContext,
+    SubordinateConfigContext,
 )
 
 from charmhelpers.contrib.openstack.utils import (
@@ -110,3 +113,44 @@ class LoggingConfigContext(OSContextGenerator):
 
     def __call__(self):
         return {'debug': config('debug'), 'verbose': config('verbose')}
+
+
+class CinderSubordinateConfigContext(SubordinateConfigContext):
+
+    def __call__(self):
+        ctxt = super(CinderSubordinateConfigContext, self).__call__()
+
+        # If all backends are stateless we can allow host setting to be set
+        # across hosts/units to allow for HA volume failover but otherwise we
+        # have to leave it as unique (LP: #1493931).
+        rids = []
+        for interface in self.interfaces:
+            rids.extend(relation_ids(interface))
+
+        stateless = None
+        any_stateless = False
+        for rid in rids:
+            for unit in related_units(rid):
+                val = relation_get('stateless', rid=rid, unit=unit) or ""
+                if val.lower() == 'true':
+                    if stateless is None:
+                        stateless = True
+                    else:
+                        stateless = stateless and True
+                else:
+                    stateless = False
+
+                any_stateless = any_stateless or stateless
+
+        if stateless:
+            if 'DEFAULT' in ctxt['sections']:
+                ctxt['sections']['DEFAULT'].append(('host', service_name()))
+            else:
+                ctxt['sections']['DEFAULT'] = [('host', service_name())]
+
+        elif any_stateless:
+            log("One or more stateless backends configured but unable to "
+                "set host param since there appear to also be stateful "
+                "backends configured.", level=WARNING)
+
+        return ctxt

hooks/cinder_utils.py

@@ -172,7 +172,7 @@ CONFIG_FILES = OrderedDict([
                           cinder_contexts.CephContext(),
                           cinder_contexts.HAProxyContext(),
                           cinder_contexts.ImageServiceContext(),
-                          context.SubordinateConfigContext(
+                          cinder_contexts.CinderSubordinateConfigContext(
                               interface='storage-backend',
                               service='cinder',
                               config_file=CINDER_CONF),

unit_tests/test_cinder_contexts.py

@@ -135,3 +135,209 @@ class TestCinderContext(CharmTestCase):
                                    'namespace': 'cinder'})
         self.assertTrue(mock_https.called)
         mock_unit_get.assert_called_with('private-address')
+
+    @patch('%s.relation_get' % (mod_ch_context))
+    @patch('%s.related_units' % (mod_ch_context))
+    @patch('%s.relation_ids' % (mod_ch_context))
+    @patch('%s.log' % (mod_ch_context), lambda *args, **kwargs: None)
+    def test_subordinate_config_context_stateless(self, mock_rel_ids,
+                                                  mock_rel_units,
+                                                  mock_rel_get):
+        mock_rel_ids.return_value = ['storage-backend:0']
+        self.relation_ids.return_value = ['storage-backend:0']
+
+        mock_rel_units.return_value = ['cinder-ceph/0']
+        self.related_units.return_value = ['cinder-ceph/0']
+
+        self.service_name.return_value = 'cinder'
+
+        settings = \
+            {'backend_name': 'cinder-ceph',
+             'private-address': '10.5.8.191',
+             'stateless': 'True',
+             'subordinate_configuration':
+             '{"cinder": '
+             '{"/etc/cinder/cinder.conf": '
+             '{"sections": '
+             '{"cinder-ceph": '
+             '[["volume_backend_name", '
+             '"cinder-ceph"], '
+             '["volume_driver", '
+             '"cinder.volume.drivers.rbd.RBDDriver"], '
+             '["rbd_pool", '
+             '"cinder-ceph"], '
+             '["rbd_user", '
+             '"cinder-ceph"]]}}}}'}
+
+        def fake_rel_get(attribute=None, unit=None, rid=None):
+            return settings.get(attribute)
+
+        mock_rel_get.side_effect = fake_rel_get
+        self.relation_get.side_effect = fake_rel_get
+
+        ctxt = contexts.CinderSubordinateConfigContext(
+            interface='storage-backend',
+            service='cinder',
+            config_file='/etc/cinder/cinder.conf')()
+
+        exp = {'sections': {'DEFAULT': [('host', 'cinder')],
+               u'cinder-ceph': [[u'volume_backend_name', u'cinder-ceph'],
+                                [u'volume_driver',
+                                 u'cinder.volume.drivers.rbd.RBDDriver'],
+                                [u'rbd_pool', u'cinder-ceph'],
+                                [u'rbd_user', u'cinder-ceph']]}}
+
+        self.assertEquals(ctxt, exp)
+
+    @patch('%s.relation_get' % (mod_ch_context))
+    @patch('%s.related_units' % (mod_ch_context))
+    @patch('%s.relation_ids' % (mod_ch_context))
+    @patch('%s.log' % (mod_ch_context), lambda *args, **kwargs: None)
+    def test_subordinate_config_context_statefull(self, mock_rel_ids,
+                                                  mock_rel_units,
+                                                  mock_rel_get):
+        mock_rel_ids.return_value = ['storage-backend:0']
+        self.relation_ids.return_value = ['storage-backend:0']
+
+        mock_rel_units.return_value = ['cinder-ceph/0']
+        self.related_units.return_value = ['cinder-ceph/0']
+
+        self.service_name.return_value = 'cinder'
+
+        settings = \
+            {'backend_name': 'cinder-ceph',
+             'private-address': '10.5.8.191',
+             'stateless': 'False',
+             'subordinate_configuration':
+             '{"cinder": '
+             '{"/etc/cinder/cinder.conf": '
+             '{"sections": '
+             '{"cinder-ceph": '
+             '[["volume_backend_name", '
+             '"cinder-ceph"], '
+             '["volume_driver", '
+             '"cinder.volume.drivers.rbd.RBDDriver"], '
+             '["rbd_pool", '
+             '"cinder-ceph"], '
+             '["rbd_user", '
+             '"cinder-ceph"]]}}}}'}
+
+        def fake_rel_get(attribute=None, unit=None, rid=None):
+            return settings.get(attribute)
+
+        mock_rel_get.side_effect = fake_rel_get
+        self.relation_get.side_effect = fake_rel_get
+
+        ctxt = contexts.CinderSubordinateConfigContext(
+            interface='storage-backend',
+            service='cinder',
+            config_file='/etc/cinder/cinder.conf')()
+
+        exp = {'sections':
+               {u'cinder-ceph': [[u'volume_backend_name',
+                                  u'cinder-ceph'],
+                                 [u'volume_driver',
+                                  u'cinder.volume.drivers.rbd.RBDDriver'],
+                                 [u'rbd_pool', u'cinder-ceph'],
+                                 [u'rbd_user', u'cinder-ceph']]}}
+
+        self.assertEquals(ctxt, exp)
+
+        del settings['stateless']
+
+        ctxt = contexts.CinderSubordinateConfigContext(
+            interface='storage-backend',
+            service='cinder',
+            config_file='/etc/cinder/cinder.conf')()
+
+        exp = {'sections':
+               {u'cinder-ceph': [[u'volume_backend_name',
+                                  u'cinder-ceph'],
+                                 [u'volume_driver',
+                                  u'cinder.volume.drivers.rbd.RBDDriver'],
+                                 [u'rbd_pool', u'cinder-ceph'],
+                                 [u'rbd_user', u'cinder-ceph']]}}
+
+        self.assertEquals(ctxt, exp)
+
+    @patch('%s.relation_get' % (mod_ch_context))
+    @patch('%s.related_units' % (mod_ch_context))
+    @patch('%s.relation_ids' % (mod_ch_context))
+    @patch.object(contexts, 'log', lambda *args, **kwargs: None)
+    @patch('%s.log' % (mod_ch_context), lambda *args, **kwargs: None)
+    def test_subordinate_config_context_mixed(self, mock_rel_ids,
+                                              mock_rel_units,
+                                              mock_rel_get):
+        mock_rel_ids.return_value = ['storage-backend:0', 'storage-backend:1']
+        self.relation_ids.return_value = ['storage-backend:0',
+                                          'storage-backend:1']
+
+        def fake_rel_units(rid):
+            if rid == 'storage-backend:0':
+                return ['cinder-ceph/0']
+            else:
+                return ['cinder-other/0']
+
+        mock_rel_units.side_effect = fake_rel_units
+        self.related_units.side_effect = fake_rel_units
+
+        self.service_name.return_value = 'cinder'
+
+        cinder_ceph_settings = \
+            {'backend_name': 'cinder-ceph',
+             'private-address': '10.5.8.191',
+             'stateless': 'True',
+             'subordinate_configuration':
+             '{"cinder": '
+             '{"/etc/cinder/cinder.conf": '
+             '{"sections": '
+             '{"cinder-ceph": '
+             '[["volume_backend_name", '
+             '"cinder-ceph"], '
+             '["volume_driver", '
+             '"cinder.volume.drivers.rbd.RBDDriver"], '
+             '["rbd_pool", '
+             '"cinder-ceph"], '
+             '["rbd_user", '
+             '"cinder-ceph"]]}}}}'}
+
+        cinder_other_settings = \
+            {'backend_name': 'cinder-other',
+             'private-address': '10.5.8.192',
+             'subordinate_configuration':
+             '{"cinder": '
+             '{"/etc/cinder/cinder.conf": '
+             '{"sections": '
+             '{"cinder-other": '
+             '[["volume_backend_name", '
+             '"cinder-other"], '
+             '["volume_driver", '
+             '"cinder.volume.drivers.OtherDriver"]]}}}}'}
+
+        def fake_rel_get(attribute=None, unit=None, rid=None):
+            if unit == 'cinder-ceph/0':
+                return cinder_ceph_settings.get(attribute)
+            elif unit == 'cinder-other/0':
+                return cinder_other_settings.get(attribute)
+
+        mock_rel_get.side_effect = fake_rel_get
+        self.relation_get.side_effect = fake_rel_get
+
+        ctxt = contexts.CinderSubordinateConfigContext(
+            interface='storage-backend',
+            service='cinder',
+            config_file='/etc/cinder/cinder.conf')()
+
+        exp = {'sections':
+               {u'cinder-ceph': [[u'volume_backend_name',
+                                  u'cinder-ceph'],
+                                 [u'volume_driver',
+                                  u'cinder.volume.drivers.rbd.RBDDriver'],
+                                 [u'rbd_pool', u'cinder-ceph'],
+                                 [u'rbd_user', u'cinder-ceph']],
+                u'cinder-other': [[u'volume_backend_name',
+                                   u'cinder-other'],
+                                  [u'volume_driver',
+                                   u'cinder.volume.drivers.OtherDriver']]}}
+
+        self.assertEquals(ctxt, exp)